Floating platform and structure pile holding force calculation method and readable storage medium

Abstract

The invention relates to the technical field of general pile holding force, and provides a floating type platform and structure pile holding force calculation method and a readable storage medium, which can efficiently and accurately calculate the general pile holding force, dynamically and accurately simulate the contact force and friction force between a clamping ring and a guide column in a three-dimensional space, and are suitable for various floating type platforms and structures. Comprising the following steps: S100, inputting a circular ring parameter, a stand column parameter and a friction parameter of a model structure; s200, calculating a contact force; s300, calculating the friction force; and S400, the pile holding force is output, and then the pile holding force is used for dynamics simulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of general pile-holding force, in particular, to a floating platform and a structure pile-holding force accurate calculation method based on dynamic contact theory and improved friction model and a readable storage medium. BACKGROUND

[0002] Floating platforms and various marine structures are widely used in shipbuilding, offshore oil and gas development, offshore wind power, and marine aquaculture. Such structures are usually fixed in place by pile-holding connection devices to resist the effects of environmental forces such as wind, waves, and currents, ensuring stability and safety during operation. Pile-holding connection devices are generally composed of guide columns (including bases) and clamps, with guide columns connected to the platform body and clamps fixed to other support structures. The contact force and friction force between the clamp and the guide column (i.e., the pile-holding force) are key factors in structural stability.

[0003] In actual working conditions, floating platforms and related structures are subjected to the combined action of various environmental forces, including wind, water flow, and wave forces. These forces not only act directly on the structure, but also indirectly affect the size and direction of the pile-holding force by causing dynamic motion of the structure (such as translation and rotation). Therefore, accurately calculating the pile-holding force under complex environmental forces is of great significance for the design of clamps and guide columns, structural stability assessment, and operational safety assurance.

[0004] Currently, there are two main methods for calculating the pile-holding force of floating platforms and structures:

[0005] 1. Specification-based calculation method: This method is based on relevant industry specifications and calculates the horizontal components of wave force, wind force, and flow force, and then adds these forces to obtain the pile-holding force. The specific steps include: calculating the effect of each environmental force on the structure according to wave theory, wind load formula, and fluid dynamics formula, and adding the horizontal component vectors to obtain the size and direction of the pile-holding force.

[0006] 2. CFD simulation-based calculation method: This method uses computational fluid dynamics (CFD) software to simulate the motion of the structure and simulates the constraints of the clamp and guide column to calculate the pile-holding force. The specific steps include: establishing a fluid dynamics model to simulate the dynamic motion of the structure under the action of wind, waves, and flow, and combining the constraints of the clamp and guide column to calculate the size and direction of the pile-holding force.

[0007] However, the above prior art does not fully consider the dynamic motion characteristics of the structure, and it is difficult to reflect the change rule of the pile holding force under actual working conditions; at the same time, the method based on CFD simulation has low calculation efficiency and poor engineering applicability, and it is difficult to meet the demand of efficient and rapid calculation; and there is no special calculation model for the contact behavior of the clamping ring and the guide column, which cannot accurately describe the nonlinear contact force and friction force between the two, resulting in insufficient accuracy of the pile holding force calculation. SUMMARY

[0008] One of the purposes of the present application is to provide a floating platform and structure pile holding force calculation method, which can efficiently and accurately calculate the general pile holding force, dynamically and accurately simulate the contact force and friction force between the clamping ring and the guide column in three-dimensional space, and is suitable for various floating platforms and structures.

[0009] The technical solution of the present application is as follows:

[0010] A floating platform and structure pile holding force calculation method, comprising the following steps:

[0011] S100: Establish a three-dimensional geometric model, input the circular ring parameters, column parameters and friction parameters of the model structure;

[0012] S200: Calculate the contact force ;

[0013] S300: Calculate the friction force using a dynamic friction force model ;

[0014] S400: Output the pile holding force: .

[0015] Further, step S200 comprises:

[0016] S210: Taking the circular ring as the reference system and the column as the moving body, calculate the position vector of the column center relative to the circular ring center ;

[0017] S220: Calculate the three-dimensional rotation matrix according to the Euler angle of the circular ring , which is used to convert the direction vector of the circular ring local coordinate system to the global coordinate system, reflecting the spatial posture of the circular ring;

[0018] S230: Calculate the contact point direction angle , accurately calculate the angular position of the contact point by the inverse tangent function;

[0019] S240: Calculate the local direction vector ;

[0020] S250: Calculate the global direction vector , transform the local direction vector to the global coordinate system by the rotation matrix;

[0021] S260: Calculate torus surface point position ;

[0022] ;

[0023] S270: Calculate column surface point position ;

[0024] S280: Calculate contact depth ;

[0025] S290: Calculate normal direction vector ;

[0026] ;

[0027] Calculate relative velocity , since the torus is stationary, the column is moving, so , the relative velocity is the velocity of the column;

[0028] Calculate contact force:

[0029] If <0, then:

[0030] Elastic force ;

[0031] Damping force .

[0032] Total contact force , where F max is the upper limit of the contact force;

[0033] Contact force vector ;

[0034] If 0, then there is no contact, the contact force is zero: .

[0035] Further, step S300 includes:

[0036] S310: Calculate relative velocity norm ;

[0037] S320: Calculate normal force norm ;

[0038] S330: Calculate relative velocity direction ;

[0039] where is a very small positive number to prevent division by zero;

[0040] : relative velocity vector;

[0041] : module (size) of relative velocity;

[0042] : unit direction vector of relative velocity;

[0043] When the module of relative velocity is greater than a minimum value , is the unit vector of relative velocity.

[0044] When the relative velocity is very small, in order to avoid division by zero, directly take the zero vector;

[0045] S340: Calculate the dynamic friction coefficient ;

[0046] where, , ;

[0047] , where v th is the characteristic velocity parameter, μ s is the static friction coefficient, and μ d is the dynamic friction coefficient.

[0048] S350: Calculate the friction force , the direction is opposite to the relative velocity.

[0049] Further, step S500 is included: at each time step, input the current state of the circular ring and the column, and calculate in turn according to the above formula to obtain the pile holding force, which is further used for dynamic simulation, including convergence judgment and iteration optimization steps:

[0050] S510: Set the convergence criterion ;

[0051] S520: Calculate the relative error of the pile holding force between the current step and the previous step:

[0052] ;

[0053] If , calculate the convergence and output the result; otherwise, update the parameters and continue iteration;

[0054] Limit the maximum number of iterations to prevent infinite loops.

[0055] Further, the three-dimensional rotation matrix in step S220 is as follows:

[0056] .

[0057] Further, the step S230 in The angle position of the contact point is accurately calculated by an arctangent function.

[0058] Further, the step S270 in ;

[0059] Wherein, .

[0060] Further, the step S280 in ;

[0061] If <0, it indicates that contact occurs, and is the overlap depth.

[0062] Further, it is suitable for different marine environmental conditions, including:

[0063] Dynamic analysis under wave load, steady-state analysis under current action, transient analysis under combined load, and through adaptive time step control to ensure calculation stability and accuracy.

[0064] Another purpose of the present application is to provide a readable storage medium, which stores a computer program, when the program is executed by a processor, the floating platform and structure pile holding force calculation method is realized.

[0065] The beneficial effects of the present application are:

[0066] The present application realizes the coupling with the structure dynamics motion model by constructing a special contact force and friction force calculation model, which can reflect the actual stress state of the structure under the action of complex environmental forces in real time.

[0067] By improving the calculation efficiency, simplifying the modeling process, enhancing the universality and engineering applicability of the model, and meeting various engineering needs such as structure design, stability evaluation and operation safety analysis.

[0068] By establishing dynamic contact point calculation, nonlinear contact force and friction force modeling and other modules, the mechanical behavior between the clasp ring and the column can be fully and accurately simulated, the accuracy and application range of the pile holding force calculation are significantly improved, and the engineering needs of various floating platforms and structure dynamics analysis under complex environment are met.

[0069] Compared with the prior art, the present application has the following obvious advantages:

[0070] 1. Dynamic and accurate modeling of contact force and friction force

[0071] The present application establishes an accurate calculation model of nonlinear contact force and friction force according to the actual contact behavior between the clamping ring and the column, can dynamically update the position and direction of the contact point in real time, and effectively simulates the change process of static friction and dynamic friction through the smooth transition of the friction coefficient. Compared with the traditional method which only uses simplified assumptions or ignores the contact behavior, the accuracy and reliability of the pile holding force calculation are greatly improved, especially suitable for dynamic analysis under complex environmental forces.

[0072] 2. High efficiency and good scalability

[0073] Adopting modular design idea, the pile holding force calculation model is independently encapsulated, which is convenient for integration with different types of dynamic simulation platform, can flexibly adapt to various engineering scenes (such as floating wind power, offshore platform, etc.), greatly improving the universality and engineering applicability of the model.

[0074] In summary, the present application is superior to the prior art in terms of calculation accuracy, efficiency and applicable range, and provides an efficient and reliable technical solution for accurate calculation of pile holding force of floating dock and similar structures. DETAILED DESCRIPTION

[0075] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0076] Embodiment 1

[0077] A floating platform and structure pile holding force calculation method is suitable for different marine environmental conditions, mechanical analysis, structural design and dynamic simulation of mooring system of various floating platforms, offshore engineering structures, floating facilities and other engineering applications. It includes dynamic analysis under wave load, steady-state analysis under current action, transient analysis under combined load, and ensures calculation stability and accuracy through adaptive time step control.

[0078] The present application can solve the problems of lack of special calculation model for dynamic contact behavior between the clamping ring and the column in the prior art, resulting in insufficient calculation accuracy of the pile holding force; and the problems of inability to accurately simulate the nonlinear contact force and friction force between the clamping ring and the column under the combined action of complex environmental forces, affecting the reliability and engineering applicability of the dynamic simulation; and the problem of poor universality of existing calculation methods, which is difficult to adapt to the dynamic analysis requirements under different structural parameters and variable working conditions.

[0079] Specifically, the method comprises the following steps:

[0080] S100: input the ring parameter, the column parameter and the friction parameter of the model structure, the ring parameter includes the inner diameter, the outer diameter and the thickness, the column parameter includes the radius and the position coordinate, the friction parameter includes the static friction coefficient and the dynamic friction coefficient, such as:

[0081] Ring parameter: mass m, inner diameter , centroid position (global coordinate) , Euler angle (describe the attitude of the ring) ;

[0082] Column parameter: radius , center position (global coordinate) , velocity (global coordinate) , contact stiffness k, damping coefficient c, maximum contact force ;

[0083] Friction parameter: static friction coefficient , dynamic friction coefficient , static friction speed threshold ;

[0084] S200: calculate the contact force ;

[0085] Wherein, the step S200 includes:

[0086] S210: taking the ring as the reference system and the column as the moving body, calculate the position vector of the column center relative to the ring center ;

[0087] S220: according to the Euler angle of the ring (θx, θy, θz) ), calculate the three-dimensional rotation matrix , which is used to convert the direction vector of the ring local coordinate system to the global coordinate system, reflecting the spatial attitude of the ring;

[0088] ;

[0089] If there is a special rotation order (such as ZYX, XYZ, etc.), it can be adjusted according to the actual engineering definition.

[0090] S230: calculate the contact point direction angle ;

[0091] The above .

[0092] This is the polar angle of the column center relative to the ring center in the XY plane, which determines the direction of the point closest to the column on the inner surface of the ring.

[0093] S240: calculate the local direction vector ;

[0094] This is the unit vector pointing to the contact point in the local coordinate system of the ring.

[0095] S250: Calculate the global direction vector , transform the local direction vector to the global coordinate system by the rotation matrix;

[0096] S260: Calculate the ring surface point position ;

[0097] ;

[0098] This is the spatial coordinate of the point on the inner surface of the ring closest to the column.

[0099] S270: Calculate the column surface point position ;

[0100] The above ;

[0101] Where, .

[0102] Ensure that the column surface point and the ring surface point are consistent in the XY plane direction and have the same Z coordinate.

[0103] Defects in the prior art: both the specification and the CFD method ignore the precise geometric contact relationship between the snap ring and the guide column, and only consider the overall structural stress.

[0104] This embodiment establishes a precise geometric positioning algorithm for the contact point between the ring and the column through this step, realizes dynamic tracking of the real contact point, and improves the contact force calculation accuracy compared with traditional overall structure analysis

[0105] S280: Calculate the contact depth ;

[0106] The above ;

[0107] If <0, it means that contact has occurred, and is the overlap depth.

[0108] If necessary, a minimum contact depth threshold can be set to avoid false contact caused by numerical errors.

[0109] The blind spot of the prior art is that the specification method and CFD simulation cannot accurately describe the dynamic change of the contact depth. Therefore, this embodiment establishes a precise contact depth model based on geometric distance, and introduces a minimum contact depth threshold.

[0110] S290: Calculate the normal direction vector ;

[0111] ;

[0112] This is the unit vector from the circular surface point to the column surface point.

[0113] Calculate relative velocity Since the circular ring is stationary, the column is moving, so The relative velocity is the velocity of the column;

[0114] Calculate contact force:

[0115] If <0 (contact occurs), then:

[0116] Elastic force 1.5 power reflects the nonlinear characteristics of Hertz contact theory;

[0117] The limitations of the prior art are as follows:

[0118] Specification method: linear superposition is used, and the contact nonlinearity is ignored;

[0119] CFD method: although it can simulate fluid nonlinearity, the contact modeling is still relatively simple;

[0120] This embodiment first introduces the 1.5 power nonlinearity of Hertz contact theory in the calculation of the holding pile force, which can accurately describe the material response under large contact pressure compared with the linear model.

[0121] Damping force Only the normal velocity component is considered.

[0122] Total contact force Where F max is the upper limit of the contact force to prevent the contact force from being too large, causing numerical instability or structural damage.

[0123] Contact force vector ;

[0124] If 0, there is no contact, and the contact force is zero: .

[0125] S300: Calculate the friction force using a dynamic friction force model ;

[0126] The dynamic friction force model considers the effect of relative velocity change on the friction coefficient;

[0127] Wherein, step S300 comprises:

[0128] S310: Calculate the relative velocity norm ;

[0129] S320: Calculate the norm of the normal force ;

[0130] S330: Calculate the relative velocity direction ;

[0131] where, is a small positive number to prevent division by zero;

[0132] : relative velocity vector;

[0133] : relative velocity module (size);

[0134] : relative velocity unit direction vector;

[0135] When the relative velocity module is greater than a small value , is the relative velocity unit vector (i.e., direction).

[0136] When the relative velocity is very small (tends to zero), in order to avoid division by zero, directly take the zero vector;

[0137] S340: Calculate the dynamic friction coefficient ;

[0138] where, when, (static friction);

[0139] when, (dynamic friction), where v th is the characteristic velocity parameter, μ s is the static friction coefficient, and μ d is the dynamic friction coefficient;

[0140] The defects of the prior art are as follows:

[0141] Standard method: completely ignore the friction effect or use a fixed friction coefficient;

[0142] CFD method: friction modeling simplification, unable to handle static and dynamic friction conversion;

[0143] This embodiment creatively uses an exponential function to achieve smooth transition of static and dynamic friction, eliminating numerical oscillation caused by sudden changes in friction, and improving stability.

[0144] S350: Calculate the friction force , opposite in direction to the relative velocity.

[0145] Opposite in direction to the relative velocity direction, and proportional in size to the normal force and the friction coefficient.

[0146] S400: Output the pile-holding force: ;

[0147] The total pile-holding force is the vector sum of the contact force (normal force) and the friction force (tangential force).

[0148] The total pile-holding force acting on the column is obtained by adding the two together.

[0149] The dynamic friction model in this embodiment adaptively adjusts the friction coefficient based on the relative speed, achieving real-time tracking of friction characteristics.

[0150] S500: At each time domain step, input the current state of the circular ring and the column, and calculate in sequence according to the above formula to obtain the pile-holding force, which is then used for dynamic simulation, including convergence judgment and iterative optimization steps:

[0151] S510: Set the convergence criterion to ensure that the calculation accuracy meets the engineering design requirements and avoids excessive iteration waste;

[0152] S520: Calculate the relative error of the pile-holding force between the current step and the previous step:

[0153] This realizes relative error calculation, avoids criterion failure under small / large force values, ensures engineering-level precision, and prevents unnecessary iteration.

[0154] If , calculate the convergence and output the result; otherwise, update the parameters and continue iteration;

[0155] Limit the maximum number of iterations to prevent infinite loops in abnormal working conditions.

[0156] The core points of this embodiment are as follows:

[0157] 1. Construction of a general pile-holding force calculation model:

[0158] A pile-holding force calculation method suitable for various floating platforms and structures is provided, which can accurately describe the dynamic contact relationship between the clamping ring and the column in three-dimensional space. This model considers parameters such as the centroid position of the circular ring (clamping ring), spatial attitude (Euler angle), spatial position and velocity of the column, etc., realizes dynamic real-time updating of the contact point position and direction, and is suitable for dynamic simulation environments of any time domain.

[0159] Geometric calculations use analytical methods instead of numerical methods, which improves efficiency compared to CFD methods.

[0160] 2. Real-time calculation method of dynamic contact point and direction:

[0161] An innovative method for calculating contact points and contact directions based on spatial geometric relationships was proposed. This method can determine the closest contact point and its normal and tangential directions in real time according to the relative position and posture changes of the ring and the column, ensuring the accuracy and timeliness of the contact force and friction force calculations.

[0162] S260-S280: Established a complete contact point positioning → contact depth calculation chain

[0163] 3. Nonlinear accurate modeling of contact force and friction force:

[0164] A normal contact force model based on contact depth and relative velocity was established, comprehensively considering elastic force (Hertz nonlinearity) and damping force, and setting a maximum contact force threshold to prevent structural failure. The friction force model uses a smooth transition algorithm for the static friction coefficient, dynamic friction coefficient, and static friction velocity threshold to accurately simulate the friction behavior between the retaining ring and the column, avoiding sudden changes in friction force and improving simulation stability.

[0165] 4. Versatility and scalability for various engineering scenarios:

[0166] This method has a high degree of parameterization and is suitable for combinations of rings and columns of different sizes and postures. It can be flexibly integrated into various floating platforms and structural dynamics simulation platforms, and has good versatility and engineering applicability.

[0167] Example 2

[0168] The difference between this embodiment and Example 1 is that, in addition to adopting the nonlinear contact force and friction force model based on contact depth and relative velocity, other contact mechanics theories, such as linear spring-damper model, Penalty method, finite element contact algorithm, etc., can also be adopted to model the contact behavior between the clamp and the column to realize dynamic calculation of the pile holding force.

[0169] Example 3

[0170] The difference between this embodiment and embodiment 1 is that, in addition to calculating the contact point and direction in real time through spatial geometric relationships, a discretization method can also be used, such as discretizing the surface of the ring and the column into multiple nodes, detecting the contact status node by node, or determining the contact point and direction based on sensor / monitoring data.

[0171] Example 4

[0172] The difference between this embodiment and embodiment 1 is that, in addition to using exponential smooth transition, other mathematical methods such as piecewise linear interpolation and hyperbolic tangent function can also be used to achieve a smooth transition between static friction and dynamic friction and avoid sudden changes in friction force.

[0173] Example 5

[0174] The difference between this embodiment and embodiment 1 is that, in addition to direct coupling with the existing dynamic simulation platform, dynamic analysis of the floating dock pile-holding force can also be achieved through custom simulation modules, co-simulation or multi-body dynamics software (such as ADAMS, Simpack, etc.).

[0175] Example 6

[0176] The difference between this embodiment and embodiment 1 is that, in addition to directly inputting the geometric and dynamic parameters of the ring and the column, embodiment 1 can also obtain relevant inputs through database calls, parametric modeling or parameter prediction methods based on machine learning to achieve automated and intelligent pile-holding force calculation.

[0177] Example 7

[0178] This embodiment provides a readable storage medium having a computer program stored thereon. When the program is executed by a processor, the method for calculating the pile-holding force of the floating platform and structure in the above-mentioned embodiments is implemented.

[0179] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for calculating the pile holding force of a floating platform and structure, characterized in that: The steps include: S100: Establish a three-dimensional geometric model and input the ring parameters, column parameters and friction parameters of the model structure; S200: Calculate contact forces ; S300: Calculate friction using a dynamic friction model ; S400: Output pile holding force: .

2. A floating platform and structure pile holding force calculation method according to claim 1, characterized in that: Step S200 includes: S210: Using the ring as the reference system and the column as the moving body, calculate the position vector of the column center relative to the ring center. ; S220: Calculate the three-dimensional rotation matrix based on the Euler angle of the ring , used to transform the direction vector of the local coordinate system of the ring into the global coordinate system to reflect the spatial posture of the ring; S230: Calculate the contact point angle ; S240: Calculate local direction vector ; S250: Calculate the global direction vector , transform the local direction vector to the global coordinate system through the rotation matrix; S260: Calculate the position of the ring surface point ; ； S270: Calculate the position of the column surface point ; S280: Calculate contact depth ; S290: Calculate normal direction vector ; ； Calculating relative speed , since the ring is stationary and the column is moving, , the relative speed is the speed of the column; Calculate contact forces: like <0, then: elastic force ; Damping force ; Total contact force , where F max is the upper limit of contact force; Contact force vector ; like 0, then there is no contact and the contact force is zero: .

3. A floating platform and structure pile holding force calculation method according to claim 2, characterized in that: Step S300 includes: S310: Calculate relative velocity norm ; S320: Calculate the normal force norm ; S330: Calculate relative velocity direction ; in, It is a very small positive number to prevent division by zero; : relative velocity vector; : the modulus (size) of the relative velocity; : unit direction vector of relative velocity; When the relative velocity modulus is greater than a minimum hour, is the unit vector of relative velocity; When the relative velocity is very small, in order to avoid division by zero, Directly take the zero vector; S340: Calculate the dynamic friction coefficient ; in, hour, ; hour, , where v th is the characteristic velocity parameter, μ s is the static friction coefficient, μ d is the coefficient of kinetic friction; S350: Calculating Friction , the direction is opposite to the relative velocity.

4. A floating platform and structure pile holding force calculation method according to claim 3, characterized in that: The process includes step S500: at each time domain step, inputting the current state of the ring and the column, and sequentially calculating according to steps S100-S400 to obtain the pile holding force, which is then used for dynamic simulation, including convergence judgment and iterative optimization steps: S510: Setting convergence criteria ; S520: Calculate the relative error between the current step and the previous step of the pile holding force: ； like , the calculation converges and the result is output; otherwise, the parameters are updated and the iteration continues; Limit the maximum number of iterations , to prevent infinite loops.

5. The method for calculating the pile-holding force of a floating platform and structure according to claim 4, characterized in that: The three-dimensional rotation matrix in step S220 The formula is as follows: 。 6. A floating platform and structure pile holding force calculation method according to claim 5, characterized in that: In step S230 , and the angular position of the contact point is accurately calculated using the inverse tangent function.

7. A floating platform and structure pile holding force calculation method according to claim 6, characterized in that: In step S270 ; in, .

8. A floating platform and structure pile holding force calculation method according to claim 7, characterized in that: In step S280 ; like <0, indicating that contact has occurred, and is the overlap depth.

9. A floating platform and structure pile holding force calculation method according to claim 7, characterized in that: Suitable for different marine environmental conditions, including: Dynamic analysis under wave loads, steady-state analysis under currents, and transient analysis under combined loads are performed with adaptive time step control to ensure computational stability and accuracy.

10. A readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed by a processor, the floating platform and structure pile-holding force calculation method according to any one of claims 1 to 9 is implemented.

Images